[Crash/Fuzzing] "TypeError: Cannot read property 'toString' of undefined" when parsing ENR string

[pventuzelo]

Describe the bug

During fuzzing with beaconfuzz, I found this TypeError crash inside the enr library when parsing invalid enr string.

Expected behavior

Should throw an Error since this string is invalid.

Steps to Reproduce

crash_TypeError_tostring_undef_enr_lodestar.js:

var discv5 = require("@chainsafe/discv5");

buf = Buffer.from('656e723a2d435972595a62404b574342526c4179357a7a61445a584a42476b636e68344d486342465a6e75584e467264764a6a5830346a527a6a7a', 'hex').toString()

discv5.ENR.decodeTxt(buf);

Run:

$ npm i @chainsafe/discv5

$ node crash_TypeError_tostring_undef_enr_lodestar.js
/home/scop/node_modules/@chainsafe/discv5/lib/enr/enr.js:76
        return this.get("id").toString("utf8");
                             ^

TypeError: Cannot read property 'toString' of undefined
    at Map.get id [as id] (/home/scop/node_modules/@chainsafe/discv5/lib/enr/enr.js:76:30)
    at Map.verify (/home/scop/node_modules/@chainsafe/discv5/lib/enr/enr.js:187:22)
    at Function.decodeFromValues (/home/scop/node_modules/@chainsafe/discv5/lib/enr/enr.js:55:18)
    at Function.decode (/home/scop/node_modules/@chainsafe/discv5/lib/enr/enr.js:62:20)
    at Function.decodeTxt (/home/scop/node_modules/@chainsafe/discv5/lib/enr/enr.js:68:20)
    at Object.<anonymous> (XXX/crash_TypeError_tostring_undef_enr_lodestar.js:5:12)
    at Module._compile (internal/modules/cjs/loader.js:936:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:947:10)
    at Module.load (internal/modules/cjs/loader.js:790:32)
    at Function.Module._load (internal/modules/cjs/loader.js:703:12)

Desktop (please complete the following information):

• OS: Ubuntu 18.04
• @chainsafe/discv5: 0.1.2
• node -v: v12.9.1

[pventuzelo]

EDIT: I've updated this issue, testing sample and error was not the good one.

[pventuzelo]

Additional information, this string is rejected by zcli with illegal base64 data error.

[twoeths]

after the fix, it should throw Error "Invalid record id"